Jesus' view on marriage is that it is to be between one man and one woman. He refers to the created order that is revealed in the book of Genesis, particularly Genesis 2:24. In this verse, we see the creation of Adam and Eve and the admonition for the man and woman to join and become one flesh. Jesus referenced them.
- Matthew 19:4-6, "And He answered and said, 'Have you not read that He who created them from the beginning made them male and female, 5 and said, ‘For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh’? 6 “So they are no longer two, but one flesh. What therefore God has joined together, let no man separate.'”
So Jesus is telling us that marriage is based on the work of God. It is he who ordained the union and established it. The original form of marriage was monogamy, not polygamy, permanence, not divorce, and it was between a man and a woman. This excludes the possibility of allowing homosexual marriage. Nevertheless, Jesus made a qualification for divorce.
Furthermore, Jesus provided for the condition of divorce in the case of sexual immorality. But he did so because of the hardness of the heart of the people.
- Matthew 19:9, “He said to them, “Because of your hardness of heart Moses permitted you to divorce your wives; but from the beginning it has not been this way. 9 And I say to you, whoever divorces his wife, except for immorality, and marries another woman commits adultery.”
- Mark 10:11-12, "And He said to them, 'Whoever divorces his wife and marries another woman commits adultery against her; 12 and if she herself divorces her husband and marries another man, she is committing adultery.'”
The word for "immorality" in the Greek in Matthew 19:9 is "porneia" and is most commonly understood to mean sexual immorality. So, if a spouse commits adultery, then the offended party has the opportunity to divorce, though not the obligation.
Some commentators have argued over the exact meaning of marriage. Some have stated that there are no grounds for divorce. But, Jesus admonition clearly contradicts them and allows for divorce. Furthermore, we can see that in the Old Testament God divorced Israel for its spiritual adultery; that is, it's idolatry.
- Isaiah 50:1, "Thus says the LORD, “Where is the certificate of divorce By which I have sent your mother away? Or to whom of My creditors did I sell you? Behold, you were sold for your iniquities, And for your transgressions your mother was sent away."
- Jeremiah 3:8, "And I saw that for all the adulteries of faithless Israel, I had sent her away and given her a writ of divorce, yet her treacherous sister Judah did not fear; but she went and was a harlot also."
So, it would seem that Jesus is acknowledging the work of God in the Old Testament regarding divorce and is reflecting upon it in his statements in Matthew 19:9 and Mark 10:11-12.
Jesus' View on marriage is that it is to be permanent unless there is adultery involved and then the offended party has the freedom to divorce, and though he did not say the obligation. In Matthew 19:4-6, Jesus refers to Old Testament Scripture regarding the created order of Adam and Eve. God made male and female, which was referenced in Genesis. Jesus was speaking about marriage, and very clearly his belief was that it was to be between a man and a woman. Therefore, homosexual marriage is excluded by Jesus.